Alloy of tantalum



[U ITED ,STATES PATENT OFFICE.

PORTER K. IRAQI, OI PITTSBURGH, PE NNSYLVANIA,ASSIGNOB TO WESTINGHOUSE & mac-mama comm, A CORPORATION 01 PENNSYLVANIA.

- annoy or rm'rnnun.

loys which strong, reasonably ducti e and resistant to oxidization.

Another object of my invention is to provide alloys, possessing the foregoing characteristics, which shall be relatively hard so that they may be employed, not only 1n the formation of acid-proof ware, but also in the manufacture of cutting tools.

A still further object of my invention resides in the formation of alloys, of the character described, which may be satisfactorily utilized in the manufacture of electricalresistance elements.

More particularly, my invention relates to alloys comprising, as one ingredient, tantalum or a metal of the tantalum group, such as columbium or niobium, together with nickel or another metal of the nickel group, such as cobalt, with, the addition of a metal of the chromium group, preferably chromium.

I have found that alloys of this character are substantially .white in color; take a fine polish and may -be worked by the usual methods, such as forging, rolling and drawing 'Such alloys are also highly resistant to acids, resistant to.oxidization, and possess, in many instances, such degree of hard ness that they may be utilized in the manufacture of cutting tools.

While the members of the tantalum group are, for my-purposes, substantial equivalents, I prefer to employ tantalum and I have found that alloys of tantalum and nickel or of tantalum and cobalt, possess great strength and considerable ductility and are highly resistant to acids. 'As a rule, I prefer to employ at least 25% tantah m and from 1% to75% nickel or cobalt,

' the two being interchangeable. An alloy of this character is highly resistant to acids and may, therefore, be utilized in the manufacture of acid-proof ware.

I employ as a hardener, in connection with I the tantalum and nickel alloy, a certain roportion ofrany of'the metals of, the c robe highl resistant to acids,

Application fled April 18, 1919: Serial no. 291,033.

mium group. For instance, an alloy highly resistant to acids. and also resistant to oxidlzatlon may comprise from. 5% to 30% chromium, together with tantalum and nickel in the proportions of 75% nickel to 25% tantalum. In place of the chromium, I may substitute molybdenum or tungsten which will harden the alloy materially, rendering it particularly adaptable for the manufacture of cutting tools. The alloys containing a metal of the tantalum group are also suitable for the manufacture of electrical-resistance elements.

" An alloy embodying my invention may be I formed by any of various well knownmethods as, for example, by mixing the metals in a powdered form, compressing them at relat vely high pressure and applying a relatively high heat in a cruciblepreviously disposed in a vacuum. The above mentioned method is set forth inthe Journal of the Iron and Steel Institute on pages 390 and 391, No. 1, 1916. The alloy may-also be readily produced by the reduction of mixed oxides of the metals as, for example, by the well known alumino-thermic methods or by reducing mixed oxides of the metals employed, to form carbides, and by subsequently melting the carbides, thus formed, in a vacuo, as described in a'copending application filed by me Apr. 18, 1919, Serial No. 291,034, and assigned to the Westinghouse Electric & Manufacturing Company.

While nickel and cobalt are substantial equlvalents, in alloys of this character, I

Their ductility is also somewhat iivhich they may be put, it will be appreck ti'ally the proportions of 1 to 75% nickelated that m invention is to be limited only and 25 to 99% tantalum,

as indicate in the appended claim. In testimony whereof, I have hereunto I0 I claim as my invention: subscribed my name this 3rd day of April, I An alloy resistant to acids and oxidiza- 1919.

tion comprising 5 to 30% chromium andthe remainder tantalum and nickel in substanv PORTER H. BRACE. 

